Avoiding scatter from strobes

Hi,

When shooting in dark water with "poor" visability, i often find it hard to get decent CFWA pictures with flash due to scatter from the strobes (like the bad example of the attached image). Does anyone have tips on how to reduce this?

Do i need longer strobe arms, less power and wider aperture?

Thanks

Tobbe

Hi,

When shooting in dark water with "poor" visability, i often find it hard to get decent CFWA pictures with flash due to scatter from the strobes (like the bad example of the attached image). Does anyone have tips on how to reduce this?

Do i need longer strobe arms, less power and wider aperture?

 

Thanks

Tobbe

Hey,

I dive in similar conditions.

How are your strobes setup?

I set my strobe arms so the strobe is as far away as possible. Then tilt the strobe outwards (away from subject.) Using a diffuser you can angle it so that only the corners of the beams hit the subject which removes scatter for me.

any other techniques?

Cal

can you post a picture of your rig with the typical cfwa setup?

i like to have my strobes in close and pointed away from parallel to the lens.

I have two Sea&sea YS-90 strobes with diffusers.

Here an image from a tropical dive, where you probably can see the rig taken by my buddy. I think i had the same strobe set-up during the cold water dive.

The answer is clear, and you do not need a longer arm:

1) pull the strobe back, until the diffuser is behind the base of your port.

2) try to avoid the 45-degree angle, opposite the cut-out on your port: 0 degrees and 90 degrees, opposite the shade, are best

3) this works, even with fisheye lenses and shorter arms

I didn't discover this, by the way. Martin Edge has it all written down!

Tim

B)

Oh, and follow Cal's advice: angle the beams outwards...

... "Don't cross the beams!" - Bill Murray? Ghostbusters!

Tim

B)

Thanks!

I'll try that!

Tim ... what does this mean:

"2) try to avoid the 45-degree angle, opposite the cut-out on your port: 0 degrees and 90 degrees, opposite the shade, are best"

Thanks!

Tim ... what does this mean:

 

"2) try to avoid the 45-degree angle, opposite the cut-out on your port: 0 degrees and 90 degrees, opposite the shade, are best"

 

Thanks!

I think this means if you have a Shade on your port, make sure the strobes are positioned to be away from the Cut-Outs on the shade. You want the port and lens to be shaded as much as possible from the light of the strobe. Moving the strobe behind the plane of the port will also accomplish this.

I am not sure I buy this 100%. I think that angleling out is most important, and that using a diffusser makes this more difficult. It is all the floaters that get illuminated in front of the port that are the problem, and no amount of shading is going to help with that.

If the hard edge from 2 cones of light meet on the subject, and the strobes are as far apart as you can manage, you will have the least amount of illuminated particulate in your frame.

I know Martin Edge has argued very well about reducing the length of strobe arms and I agree with him about stobe placement behind the horizontal plane of the port.

However I find that increasing the arm length (from 1 x 5" and 1 x 8" sections to 1 x 8" and 1 x 12") gives better results in turbid water.

Also, IMHO, not using a diffuser in turbid water seems to be a help as the 'edge' of the strobe beam appears cleaner and sharper without a diffuser and allows for more accruate lighting of only the subject. Like Martin, I use diffusers in clear tropical water.

'Edge' lighting always applies for WA and CFWA.

Tim ... what does this mean:

 

"2) try to avoid the 45-degree angle, opposite the cut-out on your port: 0 degrees and 90 degrees, opposite the shade, are best"

 

Thanks!

Dave Hicks is right. Martin has a picture in his book.

I thought that Tim M was right, until I tried shortening the arms, and with the strobes angled out, and found that short arms were just as good as long ones, but easier to dive with....

Tim

B)

The big danger in setting the lights in a convenient position is that you end up with pictures that look the same as everyone elses's.

An advertising photographer friend of mine once dryly observed that all underwater pictures looked the same and I suspect that is because we have a tendency to each position our lights in the same place.

Photography is as much about lighting as anything else and although the constraints of being under water can limit creativity, don't be fooled into simply following a formula.

Experiment!